Rotary cutting tool with coolant passages and method of making same

Abstract

A method of manufacturing a rotary cutting tool is described. The rotary cutting tool defines a central longitudinal axis and includes a shank portion and a cutting portion adjoining the shank portion. The shank portion has a shank end and the cutting portion has a cutting end opposite the shank end. One or more blades are separated by a flute. A main, internal coolant passage extends from the shank end, through the shank portion, and into the cutting portion. The method includes forming at least one secondary coolant passage in fluid communication with the main, internal coolant passage in which the at least one secondary coolant passage is formed by using electro-magnetic radiation.

What is claimed is: 
     
       1. A method of manufacturing a rotary cutting tool, the rotary cutting tool defining a central, longitudinal axis and comprising a shank portion, a cutting portion adjoining the shank portion, the shank portion has a shank end, the cutting portion has a cutting end opposite the shank end, one or more blades separated by a flute, and a main, internal coolant passage extending from the shank end through the shank portion and into the cutting portion, the method comprising:
 inserting a sacrificial rod into the main, internal coolant passage; and 
 forming at least one secondary coolant passage in fluid communication with the main, internal coolant passage using electro-magnetic radiation, 
 wherein the sacrificial rod prevents the electro-magnetic radiation from impinging on a surface of the main, internal coolant passage. 
 
     
     
       2. The method of  claim 1 , wherein the at least one secondary coolant passage is circular in cross-sectional shape. 
     
     
       3. The method of  claim 1 , wherein the at least one secondary coolant passage is non-circular in cross-sectional shape. 
     
     
       4. The method of  claim 1 , wherein the at least one secondary coolant passage is formed is formed at an angle, A 2 , with respect to the central, longitudinal axis of the rotary cutting tool. 
     
     
       5. The method of  claim 4 , wherein the angle, A 2 , is equal to 90 degrees. 
     
     
       6. The method of  claim 4 , wherein the angle, A 2 , is less than 90 degrees. 
     
     
       7. The method of  claim 4 , wherein the angle, A 2 , is greater than 90 degrees. 
     
     
       8. The method of  claim 1 , wherein the secondary coolant passage has a diameter of between 5 microns and 10 mm. 
     
     
       9. The method of  claim 1 , wherein the electro-magnetic radiation comprises a laser beam encased in a water jet. 
     
     
       10. The method of  claim 1 , wherein the electro-magnetic radiation has a non-Gaussian intensity profile. 
     
     
       11. A rotary cutting tool manufactured using the method of  claim 1 . 
     
     
       12. The rotary cutting tool of  claim 11 , wherein each blade has an end cutting edge and a peripheral cutting edge, the end cutting edge of each blade extending from an outer diameter of the cutting portion towards the central, longitudinal axis. 
     
     
       13. The rotary cutting tool of  claim 11 , wherein each secondary coolant passage has an exit aperture located in a respective flute. 
     
     
       14. The rotary cutting tool of  claim 11 , wherein the rotary cutting tool comprises a solid end mill. 
     
     
       15. The method of  claim 1 , wherein the sacrificial rod has a diameter less than a diameter of the main, internal coolant passage to enable the sacrificial rod to be easily inserted into and removed from the main, internal coolant passage of the rotary cutting tool. 
     
     
       16. The method of  claim 1 , wherein the sacrificial rod has a length greater than a length of the rotary cutting tool to enable the sacrificial rod to be easily inserted into and removed from the main, internal coolant passage of the rotary cutting tool. 
     
     
       17. The method of  claim 1 , wherein a plurality of secondary coolant passages are formed using electro-magnetic radiation. 
     
     
       18. The method of  claim 17 , wherein the plurality of secondary coolant passages are arranged in a circular array extending radially outward from the main, internal coolant passage. 
     
     
       19. The method of  claim 17 , wherein each secondary coolant passage is formed in a common plane that is substantially perpendicular to the central, longitudinal axis of the rotary cutting tool. 
     
     
       20. The method of  claim 17 , wherein at least one of the plurality of secondary coolant passages is formed at a first angle of less than 90 degrees with respect to the central, longitudinal axis of the rotary cutting tool, a second angle greater than 90 degrees with respect to the central, longitudinal axis of the rotary cutting tool, a third angle equal to 90 degrees with respect to the central, longitudinal axis of the rotary cutting tool, or any combination thereof.